COYOTE SPACE USE IN RELATION TO PREY ABUNDANCE

Food abundance is an important factor determining space use in many species, but its effect on carnivore home range and territory size has rarely been investigated. We explored the relationship between food abundance for the coyote (Canis latrans) and space use in two study areas in the northern Great Basin, where the primary prey, the black-tailed jackrabbit (Lepus californicus), fluctuates dramatically in abundance. At one site, home ranges and territories were significantly larger during a time of prey scarcity than when prey was abundant. Coyotes on the second site had similar-size home ranges and territories at low and high prey abundance, but a higher proportion and probably a higher number of individuals were transients during the prey-scarcity period. We propose mortality rates of coyotes as an important factor mediating adjustments in space use to food abundance, and suggest two mechanisms by which mortality might interact with food abundance. Higher mortality rates may simply permit more rapid adjustment of home range size to changing food conditions. Alternatively, higher mortality may selectively eliminate transients, thus reducing the impact of intruders in limiting the size of the remaining territories.